1. Field of the Invention
The invention relates to powered air purifying respirators. In one of its aspects, the invention relates to a modular powered air purifying respirator that is adapted to be removably mounted to a respirator mask and to a filter canister. In another of its aspects, the invention relates to a modular powered air purifying respirator that is adapted to be removably mounted to a hose that is connected to a respirator mask. In yet another of its aspects, the invention relates to a modular powered air purifying respirator that has a portable, rechargeable power source. In yet another of its aspects, the invention relates to a sealed modular powered air purifying respirator that has a replaceable, portable power source. In yet another of its aspects, the invention relates to a modular powered air purifying respirator which delivers a constant flow of purified air to a respirator in the event of partial filter clogging. In another of its aspects, the invention relates to a modular powered air purifying respirator with a removable battery pack.
2. Description of the Related Art
Powered air-purifying respirators (PAPRs) continually supply positive air pressure to a respirator to maintain positive pressure in the respirator. PAPRs are generally used in military, industrial or hazardous environments to provide personal respiratory protection by preventing ambient air from entering the user's mask, helmet, or hood. Respiratory hazards might include particulate matter, harmful gases, or vapors, which are removed by passing the ambient air through the filter. Typically, a powered air-purifying respirator includes a powered fan that forces ambient air through one or more filters for delivery to an inlet opening in the respirator. The fan and filter may be mounted on a facemask, or in some cases, may be mounted on a belt or backpack and connected to the facemask through a hose and a fan. Power for the fans are typically mounted remote from the facemask but can also be mounted on the mask itself.
U.S. Pat. No. 4,886,056 to Simpson discloses a positive pressure filter respirator that is mounted on a full face mask comprising an outer mask and an inner orinasal mask. The outer mask includes an air inlet to which a filter canister is screw-mounted. Immediately within the filter canister is located a centrifugal fan which is arranged to be driven by a battery operated motor so as to draw ambient air through the filter canister and into the interior of the outer mask.
U.S. Pat. No. 6,435,184 to Ho discloses a PAPR gas mask having a second filter body disposed in front of the filter body. The gas mask structure includes a rear cup body, two battery seats and a front cup body. The battery seats are respectively disposed on two sides of the bottom of the rear cup body for receiving batteries therein to provide power for a motor to drive a fan. A filter body is positioned in a fixing seat of the front cup body. A cover body is screwed on the fixing seat to fix the filter body therein and tightly hold a second filter body in front of the filter body. The fan serves to generate air flow which is filtered through the second filter body and the filter body and then conducted into the guide way of the rear cup body. The batteries are rechargeable by plugging in a charger.
U.S. Patent Application Publication No 2007/0163588 to Hebrank et al discloses a personal respirator and clean air system comprising an air mover, a particle filter, and a supply means mounted to a belt. The respirator is operably connected to a face mask by a supply hose, the opposite end of the supply hose being attached to the PAPR housing. The system typically includes a power supply, which can take the form of at least one battery or multiple batteries mounted in a cartridge, or a re-chargeable battery pack receivable in a compartment in the housing. For certain end uses, the system can instead, or in addition, include an AC adapter to allow the system to be powered off an AC outlet or to facilitate charging of the batteries. The AC adaptor can be mounted inside the housing.